Catheter-Based 24-h pH-Metry and Impedance: Technique, Interpretation, and Clinical Application

Abstract

Gastroesophageal reflux disease (GERD) is a common condition in gastroenterology practice. Classical techniques like endoscopy and 24-h pH-metry are often used to diagnose patients with symptoms related to GERD. Although these techniques have been useful over the years both for diagnosis and therapeutic guidance, there are still many patients with typical or atypical GERD symptoms with normal endoscopy and pH-metry who do not respond adequately to anti-secretory therapy. 24-h impedance combined with pH is a new technique and currently considered as the gold standard for diagnosis of GERD. It offers greater sensitivity for the detection of all reflux episodes, and allows us to establish their nature (liquid, gas, mixed), composition (acidic, non-acidic), and clearance. This chapter describes basic principles, technique, interpretation, and clinical application of 24-h pH impedance monitoring.